Ophthalmic valved trocar cannula

ABSTRACT

In various embodiments, a trocar cannula may be configured for insertion into an eye to facilitate insertion and removal of instruments during surgery. The cannula may be affixed to an overcap (to inhibit rotation of the overcap relative to the cannula) that includes a seal. In some embodiments, the seal may be overmolded into the overcap or may include a wafer that is fixed between the cannula and the overcap to inhibit rotation relative to the cannula and the overcap. In some embodiments, the cannula and overcap may snap together through a tab/slot interface in a permanent fashion such that the cannula and overcap may not be separated without damaging the cannula or overcap. In some embodiments, a vent cannula may be receivable in the slit of the seal for allowing fluids to vent from the eye through the cannula (which may include an indentation to frictionally engage the vent).

PRIORITY CLAIM

This application is a continuation application of prior U.S. patentapplication Ser. No. 12/951,266 titled “Ophthalmic Valved TrocarCannula” which was filed Nov. 22, 2010, now U.S. Pat. No. 8,277,418whose inventors are Jose Luis Lopez, Anil K. Patnala, and Mike M.Martin, which claims the benefit of priority of U.S. Provisional PatentApplication Ser. No. 61/289,449, titled “OPHTHALMIC VALVED TROCARCANNULA,” filed on Dec. 23, 2009, whose inventors are Jose Luis Lopez,Anil K. Patnala, and Michael M. Martin, both of which are herebyincorporated by reference in their entirety as though fully andcompletely set forth herein.

FIELD OF THE INVENTION

The present invention generally pertains to ophthalmic surgery. Moreparticularly, but not by way of limitation, the present inventionpertains to ophthalmic trocar cannulas and vents.

DESCRIPTION OF THE RELATED ART

Microsurgical instruments may be used by surgeons for removal of tissuefrom delicate and restricted spaces in the human body, e.g., in surgeryon the eye (such as procedures for removal of the vitreous body, blood,scar tissue, or the crystalline lens). Such instruments may include acontrol console and a surgical handpiece with which the surgeon dissectsand removes the tissue. With respect to posterior segment surgery, thehandpiece may be a vitreous cutter probe, a laser probe, or anultrasonic fragmenter for cutting or fragmenting the tissue and may beconnected to the control console by a long air-pressure (pneumatic) lineand/or power cable, optical cable, or flexible tubes for supplying aninfusion fluid to the surgical site and for withdrawing or aspiratingfluid and cut/fragmented tissue from the site. The cutting, infusion,and aspiration functions of the handpiece may be controlled by theremote control console that not only provides power for the surgicalhandpiece(s) (e.g., a reciprocating or rotating cutting blade or anultrasonically vibrated needle), but may also control the flow ofinfusion fluid and provide a source of vacuum (relative to atmosphere)for the aspiration of fluid and cut/fragmented tissue. The functions ofthe console may be controlled manually by the surgeon, (e.g., throughuse of a foot-operated switch or proportional control).

During posterior segment surgery, the surgeon may use several handpiecesor instruments during the procedure. This procedure may require thatthese instruments be inserted into, and removed out of the incision.This repeated removal and insertion may cause trauma to the eye at theincision site. To address this concern, hubbed cannulae were developedat least by the mid-1980s. These devices may include a narrow tube withan attached hub. The tube may be inserted into an incision in the eye upto the hub, which may act as a stop, preventing the tube from enteringthe eye completely. The hub may be stitched to the eye to preventinadvertent removal. Surgical instruments can be inserted into the eyethrough the tube, and the tube may protect the incision sidewall fromrepeated contact by the instruments. In addition, the surgeon may usethe instrument, by manipulating the instrument when the instrument isinserted into the eye through the tube, to help position the eye duringsurgery. Disadvantages of prior art cannulae may include the height ofthe projection on the surface of the eye, as well as the lack of anymeans to control loss of intraocular pressure during instrument exchangeor removal. The eye, being a pressurized globe, may expel aqueous orvitreous out of the open cannula when a surgical device is not present.With prior art cannulae, loss of intraocular pressure was prevented bythe insertion of a plug or cap into the tube to seal the cannula andprevent the expression of fluid and tissue. This may be a time-consumingprocess that may require additional instrumentation as well as theassistance of other operating room personnel and may increase the riskof post-operative infection.

SUMMARY OF THE INVENTION

In various embodiments, a trocar cannula may be configured for insertioninto an eye to facilitate insertion and removal of instruments duringsurgery. The cannula may be affixed to an overcap (affixed to inhibitrotation of the overcap relative to the cannula). The overcap mayinclude a seal for inhibiting the flow of fluids out of the cannula(when an instrument is not inserted) while the cannula is inserted inthe eye. In some embodiments, the seal may be molded into the overcap ormay include a wafer that is fixed between the cannula and the overcapsuch that the seal does not rotate relative to the cannula and theovercap. In some embodiments, the cannula and overcap may snap togetherthrough a tab/slot interface in a permanent fashion such that thecannula and overcap may not be separated without damaging at least partof the cannula or overcap. In some embodiments, a vent cannula may beslidably receivable in the slit of the seal for allowing fluids to ventfrom the eye through the cannula. In some embodiments, the cannula mayinclude at least one indentation to frictionally engage a portion of thevent when the vent is inserted into the cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference ismade to the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 illustrates a cannula and an overcap, according to an embodiment;

FIG. 2 illustrates the cannula affixed to the overcap, according to anembodiment;

FIG. 3 a illustrates a top view showing the slit in the seal on theovercap, according to an embodiment;

FIG. 3 b illustrates a side view of the cannula and overcap with severalexample dimensions, according to an embodiment;

FIGS. 4 a-d illustrate cross-sections of embodiments of the overcap andseal;

FIG. 5 a illustrates the cannula on a trocar inserter, according to anembodiment;

FIG. 5 b illustrates the cannula on a trocar inserter with a shippingcap, according to an embodiment;

FIGS. 6 a-b illustrates a vent, according to an embodiment;

FIG. 7 illustrates a vent in the valved trocar cannula, according to anembodiment;

FIG. 8 illustrates a cross section of the vent in the valved trocarcannula, according to an embodiment;

FIGS. 9 a-b illustrate a second embodiment of a vent;

FIGS. 10 a-c illustrate a third embodiment of a vent;

FIG. 11 illustrates a flowchart of a method for forming the valvedtrocar cannula, according to an embodiment;

FIG. 12 illustrates a flowchart of a method for forming the valvedtrocar cannula, according to another embodiment;

FIG. 13 illustrates a flowchart of a method for using the vent with thevalved trocar cannula, according to an embodiment; and

FIG. 14 illustrates a valved trocar cannula inserted into an eye,according to an embodiment.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are intended to provide a further explanation of the presentinvention as claimed.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 illustrates an embodiment of a trocar cannula 101 and an overcap103. The trocar cannula 101 may be configured for insertion into an eyeto facilitate insertion and removal of instruments during surgery. Thecannula 101 may include a shaft 105 capable of extending into the eye(e.g., through a sclera, conjunctiva, etc). In some embodiments, thecannula 101 may be attached to an overcap 103. For example, the cannula101 may include one or more tabs 107 configured to engage correspondingslots 109 on the cannula 101 (e.g., the cannula 101 illustrated in FIG.1 includes four tabs 107 to engage four corresponding slots 109 on theovercap 103). Other attachments are also contemplated. For example, thecannula 101 may include the slots and the overcap may include the tabs.In some embodiments, the cannula 101 may be attached to the overcap 103through adhesive, thermal bonding, etc. In some embodiments, a seal 111may be coupled to the overcap 103 (e.g., the seal 111 may be disposed atleast partially between the shaft 105 and the overcap 109) to form anovermolded valve. As shown in FIG. 1, a surface of the seal 111 may beexposed on the overcap 109. In some embodiments, the exposed surface ofthe seal 111 may include one or more slits 113 to allow passage ofsurgical tools into the cannula 101. In the absence of a surgicalinstrument, the seal 111 may inhibit fluid flow through the seal 111.

FIG. 2 illustrates an embodiment of the cannula 101 affixed to theovercap 103 (e.g., after engagement of the tabs 107 in respective slots109). In some embodiments, the tab/slot interface may prevent rotationof the overcap 103 relative to the cannula 101 (e.g., during insertionof the cannula 101 into the eye). In some embodiments, the tabs 107 maybe configured to permanently hold the overcap 103 to the cannula 101(such that the overcap 103 may not be removed from the cannula 101without destroying part of the cannula 101 and/or overcap 103). Forexample, the tabs 107 (and cannula 101) may be made of stainless steeland the overcap 103 may be made of plastic (e.g., polycarbonate). Othermaterials are also contemplated. The permanent hold between the overcap103 and the cannula 101 may prevent inadvertent removal of the overcap103 from the cannula 101 during surgery (e.g., vitreoretinal surgery).

FIG. 3 a illustrates a top view of an embodiment of the slit 113 in theseal 111 on the overcap 103. FIG. 3 b illustrates a side view of anembodiment of the cannula 101 and overcap 103 with several exampledimensions (provided in inches). Other dimensions are also contemplated.For example, while the outer diameter of the cannula 101 is shown as0.029 inches (corresponding to a 23 gauge cannula), in anotherembodiment, the outer diameter of the cannula may be 0.0243 inches (fora 25 gauge cannula). Other outer diameters are also contemplated.

FIGS. 4 a-c illustrate cross-sections of an embodiment of the overcap103 and seal 111. The seal 111 may be made of an elastomer (e.g.,silicone). In some embodiments, the seal 111 may be attached to theovercap 103 to inhibit rotation of the seal 111 relative to the overcap103. For example, the seal 111 may be overmolded into a depression 403and one or more holes 401 in the overcap 103. In some embodiments, theseal 111 may include a silicon wafer 405 that is formed separately fromthe overcap 103 and inserted between the overcap 103 and the cannula 101during assembly of the overcap 103 onto the cannula 101. In such a case,the seal 111 may be attached to the overcap 103 and cannula 101 througha friction fit. Other attachments are also contemplated (e.g.,adhesive).

FIG. 5 a illustrates an embodiment of the cannula 101 on a trocarinserter 501. In some embodiments, the trocar inserter 501 may include atrocar blade 503 attached to a handle 505. In some embodiments, thehandle 505 may be made of plastic and the blade 503 may be made ofstainless steel. Other materials are also contemplated. The trocar blade503 may extend past the end of the shaft 105 and may include one or moresharp edges to pierce an eye 1401 (e.g., pierce a hole through thesclera 1403 and into the vitreous body 1405) for insertion of thecannula 101. In some embodiments, a guide 507 may fit into guide slot115 to inhibit rotation of the overcap 103/cannula 101 relative to thehandle 505 during insertion of the cannula 101 into eye 1401. In someembodiments, the guide 507 may releasably engage the guide slot 115 suchthat when the trocar inserter 501 is withdrawn from the overcap103/cannula 101, the guide 507 does not pull the overcap 103/cannula 101out of the eye 1401. For example, the guide 507 may frictionally engagethe guide slot 115 with a friction force that is less than a frictionforce exerted by the eye on the external sides of the cannula 101 whenthe cannula 101 is in the eye.

While the guide 507 is depicted as a tab to be received into guide slot115, other interlocking features are also contemplated. For example, theguide 507 and guide slot 115 may include different interlocking features(such as a ring and a rod) or may include other interlocking components(e.g., interlocking magnets (one on each of the handle and overcap 103),engaging o-rings (one on each of the handle and overcap 103), etc). Insome embodiments, the guide 507/guide slot 115 interaction may preventrotation between the cannula 101 and the overcap 103 so that any angularmovement of the trocar handle 505 about the handle's axis may betransmitted to the overcap 103 and then to the cannula 101. Thisinteraction may provide vitreoretinal surgeons angular control of thecannula 101 relative to the trocar handle 505 during insertion of thecannula 101 into the sclera 1403. FIG. 5 b illustrates an embodiment ofthe cannula 101 on a trocar inserter 501 with a shipping cap 511 (whichmay be snapped on over the cannula 101 and/or over the trocar inserter501 to protect the cannula 101 and/or trocar inserter 501.

FIGS. 6 a-b illustrates an embodiment of a vent 601. While the seal 111of the valved trocar cannula may close off the cannula from fluid flowinto or out of the cannula when, for example, a surgical instrument isoccluding the cannula, a vent cannula 603 may be configured to slideinto the slit 113 of the seal 111 to allow fluids to vent from the eyethrough the cannula 101 (e.g., see FIG. 7). In some embodiments, thevent 601 may hold the seal 111 in an open position to allow fluid (e.g.,a gas or liquid) to vent through the cannula 101. For example, a gas (oranother fluid) may flow through the cannula 101 and out of vent 601during a procedure to replace the gas with another fluid. The vent 601may further include a rim 609 to provide a stop for preventing the ventfrom slipping all the way into the seal 111. The vent cannula 603 mayhave an outer diameter that is smaller than an inner diameter of trocarcannula 101 to allow the vent cannula 603 to slide past the seal 111 andinto the trocar cannula 101. The vent cannula 603 may further include arim 609 with at least one dimension that is large enough to prevent thevent 601 from slipping completely into the trocar cannula 101 (e.g., thediameter of the rim 609 may be larger than an inner diameter of thetrocar cannula 101).

In some embodiments, the vent 601 may be a separate device from thecannula to allow the vent 601 to be inserted and removed without addingor removing parts of the cannula 101 (e.g., without having to remove theovercap 103 of the cannula 101). The size of the vent 601 may also allowa user (e.g., a surgeon) to handle the vent 601 with fingers (or, forexample, forceps) during the insertion and removal of the vent 601.

In some embodiments, the vent 601 may include a flexible tube 605 (e.g.,a silicone tube) frictionally engaging the vent cannula 603. The tube605 may provide a visual indicator (e.g., be at least partiallytransparent) of the venting process (e.g., if a substance is overflowingfrom the eye (such as silicone during a viscous fluid control injectionprocedure), the silicone may flow into the tube 605 and be visible to auser. In some embodiments, the tube 605 may be used as a graspingsurface for vent removal from the cannula 101 (e.g., to assist graspingby fingers or forceps). Vent cannula 603 may include a tube portion 607configured to receive the flexible tube 605 along an outer perimeter ofthe tube 607 (which may be made of, for example, stainless steel). Insome embodiments, the tube 607 and vent cannula 603 may be formed of onepiece. FIG. 6 b illustrates several example dimensions (provided ininches), according to an embodiment. Other dimensions are alsocontemplated. In some embodiments, the dimensions of the vent 601 mayallow for the passage of instruments through the vent 601 when the vent601 is in seal 111.

FIG. 8 illustrates a cross section of an embodiment of the vent 601 inthe cannula 101. In some embodiments, the cannula 101 may include atleast one indentation 801 to frictionally engage a portion of the ventcannula 603 when the vent 601 is inserted into the cannula 101. Theindentation 801 may be dimensioned to provide enough resistance to thevent 601 to keep the vent 601 in place during a procedure. In someembodiments, the resistance between the indentation 801 and vent 601 maybe less than needed to pull the cannula 101 out of the eye whenwithdrawing the vent 601 from the cannula 101 (such that the cannula 101is not pulled out of the eye when the vent 601 is pulled out of thecannula 101 while the cannula 101 is in the eye).

Other embodiments of the vent are also contemplated. For example, anembodiment of a vent 901 is shown in FIGS. 9 a-b. As seen in FIGS. 9a-b, the vent 901 may not include a tube 605, but may instead be asingle piece. The vent 901 may be deep drawn and may include a retentionfeature for mating with a retention feature on a cannula 101. Otherformation techniques are also contemplated (e.g., the vent 901 may bemolded). In some embodiments, the vent may not include a retentionfeature. Yet another embodiment is shown as vent 1001 in FIGS. 10 a-c.Vent 1001 may include a large bell shaped inlet that may make it easierto insert and remove tools through the vent 1001 when the vent 1001 isinserted into a cannula 101. The vent 1001 may also include one or moreretention features 1003 to increase a grip between the vent 1001 and acannula 101 when the vent 1001 is inserted into a cannula 101.

FIG. 11 illustrates a flowchart of a method for forming the valvedtrocar cannula, according to an embodiment. The elements provided in theflowchart are illustrative only. Various provided elements may beomitted, additional elements may be added, and/or various elements maybe performed in a different order than provided below.

At 1101, the overcap 103 may be formed. For example, the overcap 103 maybe molded to include thru-holes 401 for receiving a silicone seal 111.Molding processes for the overcap 103 may include injection molding,compression molding, blow molding, rotational molding, etc. Othertechniques for forming the overcap 103 are also contemplated (e.g.,casting).

At 1103, the seal 111 may be overmolded onto the overcap 103. Forexample, the seal 111 may include an elastomer (such as silicone) moldedinto a depression 403 of the overcap 103 and may flow into holes 401 tosecure the seal 111 to the overcap 103. In some embodiments, the overcap103 may be placed into a mold that defines spaces through the overcap103 for the seal 111. The elastomer may then be injected into the moldand flow through the defined spaces through the overcap 103 to form theseal 111 in the overcap 103. Other manufacturing processes are alsocontemplated. For example, the seal 111 and overcap 103 may be molded asone piece (e.g., using the same material for both the overcap 103 andseal 111 in a single mold). In some embodiments, the seal 111 may beformed separately from the overcap 103 (e.g., see FIG. 10). In someembodiments, the seal may be formed with a slit 113 or the slit 113 maybe formed in the seal 111 after the seal is formed (e.g., the slit 113may be cut into the seal 111 using a sharp edge).

At 1105, a cannula 101 may be formed. For example, the cannula 101 maybe deep drawn. Deep drawing the cannula 101 may include starting with adisc of material that is pressed between one or more sets of male/femaledies to deep draw the cannula 101. A final step in cannula formation mayinclude removing excess material and/or polishing the cannula 101. Insome embodiments, material between the tabs 107 may be sheared offbetween a male and female die or may be removed in other ways (e.g., cutaway). In some embodiments, the cannula 101 may be molded (e.g.,injection molding, compression molding, blow molding, rotationalmolding, extrusion molding, etc). Other techniques for cannula formationare also contemplated. In some embodiments, the cannula 101 may be madeof stainless steel or plastic. Other materials may also be used. In someembodiments, the cannula 101 may be formed with snapping tabs 107. Forexample, the dies or mold for the cannula 101 may include spaces for theformation of the tabs or the tabs may be formed on the cannula 101through machining. Other tab forming techniques are also contemplated.

At 1107, the overcap 103 may be affixed to the cannula 101. For example,the tabs 107 may be snapped into corresponding slots 109. In someembodiments, the overcap 103 may slightly deform to receive the tabs 107or the tabs 107 may be configured to slightly deform as the overcap 103is pressed onto the cannula 101 and then return to their initialcondition as the corresponding slots 109 of the overcap 103 pass overthe tabs 107. The tabs 107 may be rigid enough (e.g., made of stainlesssteel) such that the overcap 103 may not be removed from the cannula 101without destroying part of the cannula 101 and/or overcap 103.

FIG. 12 illustrates a flowchart of a method for forming the valvedtrocar cannula according to another embodiment. The elements provided inthe flowchart are illustrative only. Various provided elements may beomitted, additional elements may be added, and/or various elements maybe performed in a different order than provided below.

At 1201, an overcap 1103 may be formed (e.g., through molding). In someembodiments, the overcap 1103 may be formed with receiving slots 109.

At 1203, a seal 111 (such as a silicone wafer 405) may be formed. Insome embodiments, the silicone wafer 405 may be molded with a slit 113or the slit 113 may be formed in the silicone wafer 405 after molding(e.g., the slit 113 may be cut into the silicone wafer using a sharpedge).

At 1205, the cannula 101 may be formed. For example, the cannula 101 maybe molded out of stainless steel and may include tabs 107.

At 1207, the silicone wafer 405 may be inserted between the cannula 101and overcap 103 and the overcap 103 may be affixed to the cannula 101(e.g., the overcap 103 may be snapped onto the cannula 101 such that theslots 109 may receive tabs 107).

FIG. 13 illustrates a flowchart of a method for using the vent with thevalved trocar cannula, according to an embodiment. The elements providedin the flowchart are illustrative only. Various provided elements may beomitted, additional elements may be added, and/or various elements maybe performed in a different order than provided below.

At 1301, the trocar blade 503 may be inserted through the slit 113 inthe seal 111 and through cannula 101. At 1303, the eye 1401 may bepierced with the trocar blade 503 and the cannula 101 may be pushed intothe eye. At 1305, the trocar blade 503 and cannula 101 may be rotated asneeded during the insertion. At 1307, the trocar blade 503 may bewithdrawn leaving the cannula 101 in the eye 1401. At 1309, a vent 601may be inserted as needed to open the seal 111 to allow fluid/gas tovent through the cannula 101 and out of the eye 1401. The vent 601 maybe removed and/or reinserted as needed into the seal 111 and cannula 101without withdrawing the cannula 101 from the eye during the procedure.Inserting the withdrawing the vent 601 may be performed using, forexample, the user's fingers or a pair of forceps.

Various modifications may be made to the presented embodiments by aperson of ordinary skill in the art. Other embodiments of the presentinvention will be apparent to those skilled in the art fromconsideration of the present specification and practice of the presentinvention disclosed herein. It is intended that the presentspecification and examples be considered as exemplary only with a truescope and spirit of the invention being indicated by the followingclaims and equivalents thereof.

What is claimed is:
 1. An apparatus, comprising: a cannula configuredfor insertion into an eye; an overcap affixed to the cannula; whereinthe cannula or the overcap includes at least one tab and wherein theother of the cannula or overcap includes at least one slot, wherein atab of the at least one tab extends along less than three hundred andsixty degrees of a peripheral of the cannula or the overcap and whereina slot of the at least one slot terminates in an overlapping portion ofthe peripheral of the cannula or the overcap that does not include thetab; wherein the overcap is affixed to the cannula by the at least onetab being received in the at least one slot; wherein the overcap isconfigured not to rotate relative to the cannula; and a seal between thecannula and the overcap, wherein the seal is configured to allow passageof a surgical tool into the cannula through a slit in the seal whileinhibiting fluid flow through the seal when the surgical tool is notpresent in the seal.
 2. The apparatus of claim 1, wherein the seal isovermolded into a depression in the overcap.
 3. The apparatus of claim2, wherein the seal is molded into at least one hole in the overcap. 4.The apparatus of claim 1, further comprising a vent cannula configuredto slide into the slit of the seal for allowing fluids to vent from theeye through the cannula.
 5. The apparatus of claim 4, wherein thecannula comprises at least one indentation to frictionally engage aportion of the vent cannula when the vent cannula is inserted into thecannula.
 6. The apparatus of claim 1, wherein the overcap comprises aguide slot, wherein the guide slot is configured to receive a guide tabfrom a trocar handle and wherein interaction between the guide slot andthe guide tab inhibit rotation of the overcap relative to the handleduring insertion of the cannula into the eye.
 7. The apparatus of claim6, wherein the guide slot is along an outer circumference of theovercap.
 8. The apparatus of claim 6, wherein the guide tab extends froman outer circumference of the trocar handle.